Field of the Invention
The present invention relates to a concentration measuring method related to a concentration of a predetermined chemical component in a liquid or a gas, a sugar content in a fruit or a vegetable, a sake meter value (sweetness/dryness) of Japanese sake, or the like.
Description of the Background Art
In the manufacture of a semiconductor, mixed gases are often supplied from the same line inside a treatment chamber of a semiconductor manufacturing device. The supply of such a mixed gas requires that a mixture ratio of component gases be kept constant during the treatment process period, and instantaneously changed as intended. To this end, a flow rate control device, such as a flow control system component (FCSC), for example, that comprises a gas flow rate measurement mechanism and a gas flow rate adjustment mechanism is arranged in the gas supply line. In this FCSC, the degree to which the flow rate per unit time (hereinafter also referred to as “unit flow rate”) of each component gas that constitutes the mixed gas can be accurately measured is important.
Today, in a semiconductor manufacturing process in which there are many opportunities to implement a treatment process such as film formation or etching at an atomic- to nano-order level, the unit flow rate of each component gas in a mixed gas immediately prior to introduction to a treatment chamber needs to be measured accurately and instantaneously down to a range of a small amount.
In such a conventional flow rate control device that satisfies the requirement described above, generally the flow rate of each single component gas prior to mixture is measured and the target mixture ratio of the mixed gas is calculated from the measured flow rate values.
Nevertheless, the mixture ratio of the mixed gas at the moment of introduction into the treatment chamber (hereinafter also referred to as “actual mixture ratio”) is not always guaranteed to be the same as the mixture ratio calculated from the measured flow rate values (hereinafter also referred to as “measured mixture ratio”) during process execution. Thus, conventionally a feedback mechanism is provided that measures the flow rate of each single component gas either continually or at a predetermined interval, and adjusts each of the flow rates so that, when the flow rate of any single component gases fluctuates, the mixture ratio becomes the original predetermined mixture ratio based on the new value (Patent Document 1, for example).
On the other hand, examples of a gas concentration measuring system include a system that uses a partial pressure measurement sensor that measures the partial pressure of a material gas by a non-dispersive infrared absorption method, and calculates the concentration of the material gas on the basis of the partial pressure measurement value of this sensor by a mathematical operation (Patent Document 2, for example).
Further, in metal-organic compound chemical vapor deposition (MOCVD; chemical vapor deposition that uses a metal-organic compound) as well, formation of a uniform film requires control of the supplied concentration of the metal-organic compound so that the supplied concentration of the metal-organic compound is constant during the film formation process period, or so that the supplied concentration fluctuates in accordance with the component distribution of the metal-organic compound to ensure formation of a film with a preferred component distribution. Generally, the metal-organic compound is mixed into a carrier gas via bubbling or the like, and supplied to the treatment chamber. The used metal-organic compound is not limited to a single compound, and a plurality of compounds may be used as well. Examples of the method used to supply the raw material gases of a plurality of types of metal-organic compounds in accordance with design values include a method for using infrared gas analysis means (Patent Document 3, for example).
Furthermore, in the field of fruit and vegetable production and shipping as well, measurement of the concentration of a component such as a sweetness component of the fruit or vegetable is important in determining the sales price of the fruit or vegetable to be shipped. That is, the sweetness of a fruit or vegetable such as an apple, pear, peach, persimmon, strawberry, or watermelon significantly affects the sales price of the product, and thus knowing whether or not the sweetness is ideal for harvest for shipping is a matter of keen interest to the fruit and vegetable producer. One method for ascertaining the sweetness of a fruit or vegetable is to measure the sugar content in the fruit or vegetable in a non-contact manner using infrared light (Patent Document 4, for example).
Further, medically related, the ability to instantaneously measure blood components in the bloodstream, for example, such as the red blood cell count, white blood cell count, platelet count, reticulocyte count, and hemoglobin level in a living body in a non-contact (non-destructive, non-invasive) manner without drawing blood would not only alleviate the burden of the patient but also mentally and physically alleviate the labor burden of doctors, nurses, and medical technicians. Thus, the ability to easily and instantaneously take such measurements in a living body in a non-contact, non-invasive manner has been desired. For example, recently the number of diabetes patients in younger demographics is on the rise, increasing the demand for test methods that allow tests to be conducted easily, quickly, and with high accuracy. Furthermore, not only are there many patients under doctor care, but there are many latent patients (potential patients) as well, and the number of cases in which, for example, such a patient experiences a sudden drop in blood sugar level while driving, fully or partially loses consciousness, and causes an accident is increasing daily. While the concentration of glucose (blood sugar level, blood sugar) in the blood is normally continually adjusted within a certain range by the activity of various hormones (insulin, glucagon, cortisol, and the like), when this adjustment mechanism fails for any of a variety of reasons, the amount of sugar in the blood increases abnormally, resulting in diabetes. Diabetes is a disease that refers to a condition in which the blood sugar level (concentration of glucose in the blood) is abnormally high, and is diagnosed when the blood sugar level or hemoglobin Alec value exceeds a certain standard. Diabetes may cause symptoms attributable to the high blood sugar itself and also, over time, glycation in which glucose, having a high concentration in the blood, binds with protein in the vascular endothelium due to the high reactivity of the aldehyde group, resulting in the gradual destruction of microvessels in the body, causing serious disorders (microangiopathies including diabetic neuropathy, diabetic retinopathy, and diabetic nephropathy) in various organs in the body, including the eyes and kidneys (complications). Thus, appropriate blood sugar management is important in the treatment of diabetes, including continual strict blood sugar control, medical diet and therapeutic exercise review, insulin dose adjustment and review, verification/prediction of low blood sugar by medical treatment, alleviation of low blood sugar anxiety, and avoidance of severe hyperglycemia.
Measurement of blood sugar level in medical institutions such as hospitals is generally performed by a so-called invasive method for drawing blood from a finger, arm, or the like of the living body. Further, diabetes patients are tested for blood sugar level during treatment under the care of a physician in the hospital. On the other hand, in many cases the blood sugar level needs to be measured daily, and thus a patient must often perform blood sugar level measurements on his or her own using a self-monitoring of blood glucose (SMBG) device in a hospital bed or at home. While measurement has become rather simple, blood still must be drawn either by the patient or with the help of another. Blood is drawn by puncturing a finger or an arm. This puncturing is associated with pain and a puncture wound, placing physical and mental stress on the patient. While recently the use of a painless needle may be considered, association with a puncture wound cannot be avoided, and health safeguards for preventing infection caused by open wounds and the like are required. Recently, as a solution to this problem, non-invasive methods are proposed (Patent Documents 5 and 6, for example).
On the other hand, in Japan, both the blood sugar level and the hemoglobin A1c value must be measured to assess diabetes. Examples of methods for measuring both the blood sugar level and the hemoglobin A1c value include the method set forth in Patent Document 7.
Furthermore, a method that allows measurement of a sake meter value (hereinafter “SMV”), acidity, and amino acidity in the manufacturing process of Japanese sake, with high accuracy, promptness, and a simple configuration, has been in demand. Japanese sake is a liquor delicate in flavor and aroma. Japanese sake is gauged in terms of sweetness/dryness by its SMV, and in terms of full-bodied/light flavor by its acidity. The SMV refers to the amount of sugar and acid dissolved in the sake, and is a unit that expresses the specific gravity of the refined sake. The SMV is measured by bringing the temperature of the sake to be measured to 15° C., and then floating a hydrometer called an SMV meter in the sake. Japanese sake having the same weight as distilled water at 4° C. is given an SMV of “0.” Any lighter sake is indicated by a positive (+) value, and any heavier sake is indicated by a negative (−) value. In Japanese sake, what determines sweetness is glucose concentration.
In contrast to SMV which gauges sweetness/dryness, acidity (level of light/full-bodied flavor) gauges richness and depth. A Japanese sake with a higher acidity has a more full-bodied flavor, while a Japanese sake with a lower acidity has a lighter flavor. Given the same SMV, a Japanese sake with a high acidity is spicier while a sake with a low acidity is sweeter. Conversely, a Japanese sake with low acidity tends to lack a smooth, clean finish, and have a shallow flavor. This acidity, however, affects not only richness, but the actual sweet/spicy flavor as well. In general, a higher acidity tends to result in a spicier taste. Conversely, a low acidity results in a sweeter taste, even if the sugar content is not high. Acidity is measured by the number of titration millimeters of a 1/10 normal sodium hydroxide solution that is required to neutralize 10 milliliters of the refined sake. If this value is high, expressions such as “plain” are used. If this value is low, expressions such as “rich” are used. Further, with Japanese sake, amino acidity (tastiness) is also important. Amino acids are elements that bring savoriness, and high amino acidity results in an increase in savory elements, and thus a rich sake flavor. However, savoriness does not necessarily increase as the amino acidity is increased, resulting in an off-flavor when too high.
As described above, in the manufacture of Japanese sake, the management of SMV, acidity, and amino acidity significantly affects the business value (hereinafter also referred to as “sales value”) of the manufactured sake. The SMV, acidity, and amino acidity sensitively fluctuate according to humidity, temperature, and sanitary aspects, and thus humidity, temperature, and sanitary aspects are strictly controlled in the manufacture of Japanese sake and SMV, acidity, and amino acidity are frequently measured in the manufacturing process.